First, that is some awsome work.
First the machine. The one you posted looks as if it is basicly a router. I wouldn't call it a milling machine, but it should do OK for light dutty cuttinig. The work envlope is something to consider. The machines never seem to be big enough after your first couple jobs. Ihave a Taig mill that I did a CNC conversion on. It's limits are X-12",Y-5.5", and Z-6".out ofthe 6" Z, you have to consider the tooling length and work setup.I don't know the maximum size you will be working with, but take that size and add a couple inches for clamps and such on each end and side and you should be good to go.
The Cad software I use is Rhino 3D. I looked at a lot of different packages, but this one seem to fit me. Ican make simple 2D drawings or complex full 3d ones. Imostly work in 2 and 2 1/2D works. From Rhino, Ican output an STL file for Meshcam for 3|D milling, or a DXF file for SheetCam whiich Iuse mostly. The 1/2D is accomplished with depth of cuts and layered drawings. I tend to favor Sheetcam as it is very powerful and not very expensive. Both Mesh Cam and SheetCam outputs Gcode. That Gcode is fed into the last software backage, Mach3, which converts the G code to move instructions for your machine. Again, it is avery powerful software package at a reasonable price. Mach3 runs on the PCthat controls my mill electronics. Rhino, Meshcam, and Sheetcam all run on my office machine.
You can download and try all of these.
$995 (student price is $195, and it is full featured, but not for comerical use)
There are bundles of Sheetcam/Mach3, and Meshcam/Mach3. that will bring the total down a bit.
These are what I use. There are a lot of other packages out there, most are more expensive, few have more power and flexability. Some are just junk, and others are highly recomended. You have a lot of choices.